A number of benzodiazepine compounds exhibit excellent depressant activity on the central nervous system (CNS) such as sedative, muscle relaxant and anticonvulsant activity, and some of the compounds are used widely as minor tranquillizers and anticonvulsants in the clinical field.
Thienodiazepine compounds are also known to exhibit excellent depressant activity on CNS as disclosed, for example, by M. Nakanishi et al. in Journal of Medicinal Chemistry, Vol. 10, No. 3, pp. 214-219 (1973).
On the contrary, thiendiozepines of the present invention exhibit remarkably different activity compared with the known diazepine compounds, namely it is found that the thienodiazepines of the present invention exhibit more potent in analgesic activity and less potent in CNS depressant activity. Analgesic activity of the known diazepine compounds is fairly weak, and that analgesic activity thereof may be attributed to a secondary induction from CNS depressant activity.
The Japanese Patent Application Publication No. 71-39349 (cf. Chemical Abstracts Vol. 76, 46225z (1972)) and U.S. Application Ser. No. 242768 now Pat. No. 3,840,558 disclose 1-dimethylcarbamoylbenzodiazepine compounds and 1-monomethylcarbamoylthienodiazepine compounds as having utility as minor tranquillizers and anticonvulsants.
We have disclosed a prototype of thienodiazepines having utility as analgesics.